The invention relates to a method and system integrated with a battery for monitoring and displaying to a user of the battery on a real time basis the state of health of the battery by determining the state or condition of various battery factors.
Knowledge of the state-of-health (SOH) of a battery installed on board a vehicle such as an automobile, aircraft, boat, or in a mission critical application, such as an uninterruptible power supply (UPS), is often required to ensure reliable operation of the vehicle or electrical system operated by the battery. Factors of the battery state of health include, among others, its load handling capability, state-of-charge (SOC) and low temperature starting limit. The current approach in the industry to determine factors indicative of battery state-of-health (SOH) is to perform the necessary tests in a laboratory or garage to determine battery SOC and other factors before installing the battery in the vehicle or other system. This approach is very time consuming and, to save time, sometimes only the battery voltage is measured before installation. This measurement alone is not indicative of the true status of the battery state of charge (SOC) and load handling capability under various operating conditions needed to be determined to ensure reliable operation of the battery in the vehicle or system in which it is to be installed. In addition, these techniques do not determine factors related to the battery SOH as it is operating under load in the vehicle or system.
A need exists to monitor these battery factors in a simple and reliable manner on a real time basis under all operating conditions with the battery installed in the vehicle or system to provide a more reliable and meaningful representation of the battery SOH. It is also desirable to display the state of these factors in a manner to be readily available to the operator of the vehicle or system in which the battery is installed.
The invention provides a system and method to provide accurate determination of various factors related to the SOH of a battery. The system includes the circuitry of the invention preferably mounted on or installed integral with the battery, although it can be located at a remote point in the vehicle or at another location. In accordance with the invention, measurements of battery temperature, battery voltage and current into and out of the battery are made on the battery while it is operating under load. From this data the system calculates the battery""s internal resistance (IR) and its polarization resistance (PR). Utilizing the measured voltage, current and temperature parameters, and the calculated IR and PR, the circuit calculates other factors such as battery capacity, SOC and Cold Cranking Amperes (CCAs). These factors of the battery""s health and status can be displayed directly at the battery or at a remote location. Availability of this data makes the battery xe2x80x9csmartxe2x80x9d and indicates its usefulness to the user under actual performance conditions. That is, the user is able to readily determine on a real time basis under operating conditions if the battery can satisfy the application for which it is being used or if it needs to be replaced.
It is an object of the invention to provide a system and method to measure, compute and display various functional factors of a battery related to its SOH under all operating states of the battery.
Another object is to provide a system and method integral with a battery to determine, compute and display in real time various factors relative to its state of health (SOH) while the battery is operating in the system in which it is installed.
A further object is to provide a system and method that monitors and displays various factors of a battery""s condition relative to its state-of-health on a real time basis as the battery is used under load.